package com.njust.interceptor;

import com.baomidou.mybatisplus.core.toolkit.StringUtils;
import com.njust.Util.JwtUtil;
import com.njust.context.BaseContext;
import com.njust.domain.po.User;
import com.njust.exception.TokenInvalid;
import com.njust.exception.TokenIsNull;
import com.njust.mapper.UserMapper;
import io.jsonwebtoken.Claims;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.Objects;

/**
 * jwt令牌校验的拦截器
 */
@Component
@Slf4j
public class JwtInterceptor implements HandlerInterceptor {

    @Autowired
    private UserMapper userMapper;

    /**
     * 校验jwt
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        if(!(handler instanceof HandlerMethod)){
            return true;
        }
        //1、从请求头中获取令牌
        String token = request.getHeader("token");
        //2. 校验令牌
        if(StringUtils.isBlank(token)){
            throw new TokenIsNull("token为空,未登录");
        }
        //2、校验令牌
        try {
            log.info("jwt校验:{}", token);
            Claims claims = JwtUtil.parseJWT(token);
            Integer uId = Integer.valueOf(claims.get("uId").toString());
            User user=userMapper.selectById(uId);
            if(uId==null||Objects.isNull(user)){
                throw new TokenInvalid("token非法");
            }
            log.info("当前用户id：{}", uId);

            BaseContext.setCurrentId(uId);
            //3、通过，放行
            return true;
        } catch (Exception ex) {
            //4、不通过，响应401状态码
            response.setStatus(401);
            return false;
        }

    }
}
